27-sept. 2001atnf synthesis workshop spectral line image analysis and visualization bärbel...
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27-Sept. 2001 ATNF Synthesis Workshop
Spectral Line Image Spectral Line Image Analysis Analysis and Visualizationand Visualization
BBäärbel Koribalskirbel Koribalski
(ATNF, CSIRO)(ATNF, CSIRO)
27-Sept. 2001 ATNF Synthesis Workshop
Interesting spectral Interesting spectral lines, lines, e.g.e.g.
HIHI (21-cm, 1420.405 MHz)(21-cm, 1420.405 MHz) !!! !!! = neutral atomic = neutral atomic hydrogen hydrogen
HCNHCN (3mm, 89632 MHz)(3mm, 89632 MHz) = molecular hydrogen cyanid= molecular hydrogen cyanid
SiOSiO (3mm, 86243 MHz)(3mm, 86243 MHz) = maser line= maser line
… … many, many, many moremany, many, many more
27-Sept. 2001 ATNF Synthesis Workshop
Let’s concentrate on HI :Let’s concentrate on HI : There is lots of neutral hydrogen gas There is lots of neutral hydrogen gas
in galaxies -> in galaxies -> HI is easyHI is easy to detect to detect HI traces the HI traces the large-scale structure and large-scale structure and
kinematicskinematics of galaxies of galaxies HI rotation curveHI rotation curve -> gas and total -> gas and total
massmass HI also traces HVCs and tidal gas HI also traces HVCs and tidal gas
clouds -> study clouds -> study galaxy collisionsgalaxy collisions HI emission and absorption studiesHI emission and absorption studies
27-Sept. 2001 ATNF Synthesis Workshop
1. Experiment 1. Experiment (quick and (quick and dirty)dirty)
HI snapshot observationsHI snapshot observations e.g., observe 5 galaxies for 10 min. e.g., observe 5 galaxies for 10 min.
each plus nearby phase each plus nearby phase calibrator(s)calibrator(s)
repeat 12 times to obtain 12-hour repeat 12 times to obtain 12-hour uv-coverageuv-coverage
make imagesmake images get galaxy positionsget galaxy positions
27-Sept. 2001 ATNF Synthesis Workshop
The new galaxyThe new galaxy HIPASS J1559-HIPASS J1559-61016101
27-Sept. 2001 ATNF Synthesis Workshop
The new galaxyThe new galaxy
HIPASS J1559-6101:HIPASS J1559-6101: but where is it ?but where is it ?
Optical DSS image centered on the HIPASS position
27-Sept. 2001 ATNF Synthesis Workshop
ATCA HI snapshot ATCA HI snapshot observationobservation
5 x 10 min. data
e.g. in miriad
• atlod
• uvplot
vis=my.uv axis=uu,vv options=nobasedevice=/xw
27-Sept. 2001 ATNF Synthesis Workshop
1) Find the signal !
• atlod in = *.C942 out=my.uv options=hanning,bary
• uvsplit vis=my.uv
• uvspec vis=mygal.1402 interval=1000 device=/xw options=nobase,avall
Uncalibrated HI spectrum
27-Sept. 2001 ATNF Synthesis Workshop
HI emission approx. in channels 155 - 170
27-Sept. 2001 ATNF Synthesis Workshop
2) Calibration
3) Continuum subtraction• mfcal
• gpcopy
• gpcal
• gpboot
• uvlin
Calibrated & continuum- subtracted
HI spectrum
27-Sept. 2001 ATNF Synthesis Workshop
HI emission in the velocity range 4080 - 4140 km/s
27-Sept. 2001 ATNF Synthesis Workshop
“dirty” channel maps (before cleaning)
task invert
27-Sept. 2001 ATNF Synthesis Workshop“dirty” beam
27-Sept. 2001 ATNF Synthesis WorkshopCLEANed channel maps
tasks clean & restor
27-Sept. 2001 ATNF Synthesis Workshop
HIPASS J1559-HIPASS J1559-
6101:6101: Good position, Good position, but no optical but no optical counterpart.counterpart.
ZOA
27-Sept. 2001 ATNF Synthesis Workshop
Moment mapsMoment maps … … are very are very usefuluseful
= intelligent cube compression= intelligent cube compression 0. mom0. mom = integrated HI intensity = integrated HI intensity1. mom1. mom = mean HI velocity field = mean HI velocity field2. mom2. mom = mean HI velocity dispersion = mean HI velocity dispersion -> see Chapter 12.11-> see Chapter 12.11
task task momnt momnt or or xmom xmom in in AIPSAIPS; ; task task moment moment in in MIRIADMIRIAD; etc.; etc.
27-Sept. 2001 ATNF Synthesis Workshop
Pair Pair (v_HI = 2676 (v_HI = 2676 km/s)km/s)
ATCA HI snap-shot observation
ESO122-IG002(v = 2744 km/s)
ESO122-IG001(v = 2598 km/s)
27-Sept. 2001 ATNF Synthesis Workshop
Group Group (v_HI = 2453 (v_HI = 2453 km/s)km/s)
ATCA HI snap-shot observation
NGC2222(v = 2602 km/s)
ESO161-G001(v = ?)
NGC2221(v = 2532? km/s)
27-Sept. 2001 ATNF Synthesis Workshop
2. Experiment 2. Experiment
deep HI observationsdeep HI observations e.g., observe 3 x 12 hours with e.g., observe 3 x 12 hours with
various arrays (375, 750, 1.5)various arrays (375, 750, 1.5) calibrate and combine datacalibrate and combine data find HI emission / absorption find HI emission / absorption make channel maps make channel maps (movies)(movies)
make moment maps etc.make moment maps etc.
27-Sept. 2001 ATNF Synthesis Workshop
The starburst galaxy NGC The starburst galaxy NGC 253253
bright spiral bright spiral galaxygalaxy
edge-on edge-on member of the member of the
Sculptor GroupSculptor Group large amount of large amount of
star formation in star formation in the nuclear regionthe nuclear region
27-Sept. 2001 ATNF Synthesis Workshop
NGC 253NGC 253
global HI global HI spectruspectrumm
27-Sept. 2001 ATNF Synthesis Workshop
V
E
L
O
C
I
T
Y
-200 km/s
+200 km/s
v_sys
How does the rotation curve look like ?
27-Sept. 2001 ATNF Synthesis Workshop
Radial distribution
Model velocity field: ``spider diagram’’
Rotation curve
27-Sept. 2001 ATNF Synthesis Workshop
The starburst galaxy NGC The starburst galaxy NGC 253253
HI intensity HI intensity distributiondistribution
HI velocity field (top)
27-Sept. 2001 ATNF Synthesis Workshop
NGC 253 movieNGC 253 movie (program (program krot)krot)
27-Sept. 2001 ATNF Synthesis Workshop
Channel maps of a model galaxy
Position velocity diagrams along
a) the major axis
b) the minor axis
27-Sept. 2001 ATNF Synthesis Workshop
The Circinus Galaxy: The Circinus Galaxy: channel channel mapsmaps
27-Sept. 2001 ATNF Synthesis Workshop
The Circinus GalaxyThe Circinus Galaxy
HI intensity HI intensity distributiondistribution
HI velocity field (top)
27-Sept. 2001 ATNF Synthesis Workshop
The Circinus GalaxyThe Circinus Galaxy
in ZOA, b = -4 degrin ZOA, b = -4 degr optically obscuredoptically obscured only discovered in only discovered in
1977 by K. 1977 by K. Freeman and Freeman and collaboratorscollaborators
starburst galaxystarburst galaxy active nucleusactive nucleus strong masersstrong masers
27-Sept. 2001 ATNF Synthesis Workshop
The galaxy pair The galaxy pair NGC4038/9NGC4038/9
““The Antennae’’The Antennae’’ nearby pair of nearby pair of
merging galaxiesmerging galaxies prominent tidal tails prominent tidal tails
in the optical and HIin the optical and HI star formation in the star formation in the
nuclear disksnuclear disks one companionone companion new dwarf galaxy in new dwarf galaxy in
formation formation
27-Sept. 2001 ATNF Synthesis Workshop
The galaxy pair NGC4038/The galaxy pair NGC4038/9 9
HI intensity HI intensity distributiondistribution
HI velocity field (top)
27-Sept. 2001 ATNF Synthesis Workshop
27-Sept. 2001 ATNF Synthesis Workshop
NGC7582/90/99: part of NGC7582/90/99: part of the Grus Quartettthe Grus Quartett
HI intensity HI intensity distributiondistribution
HI velocity field (top)
27-Sept. 2001 ATNF Synthesis Workshop
VX Sgr: VX Sgr: SiO maser @ 86.243 SiO maser @ 86.243 GHzGHz
ATCA – Narrabri
31 m baseline
SiO : 86.243 GHz
BW = 16 MHz
channels = 512
ATCA – Narrabri
31 m baseline
SiO : 86.243 GHz
BW = 16 MHz
channels = 512
SESTSEST
ATCAATCA
27-Sept. 2001 ATNF Synthesis Workshop
Highlight of the night !Highlight of the night ! (December 10th, (December 10th,
2000)2000)
ATCA - Narrabri
HCO+ : 89.188 GHz
BW = 32 MHz
channels = 128
31 m baseline
ATCA - Narrabri
HCO+ : 89.188 GHz
BW = 32 MHz
channels = 128
31 m baseline
HCO+ absorption in the galaxy Centaurus A
©ATCA
Cen A